MORPHOLOGY AND EVOLUTION
Man. but the reverse is the case in the Apes of the family Simiidae. In the Macaques the anterior bellies act as lingual supports. The anterior bellies have undergone reduction in the Anthropoids, and Smith Woodward
FIG. 32.—The cervical muscles in the Chimpanzee. D.AI., digastric muscle ; S-M.3£.and C-M.M., sterno-mastoid and cleido-mastoid; S-H.M. and Sy-H.31., sterno-hyoid and stylo-hyoid muscles; 0-H.M.,omo-hyoid ; S-T.M., sterno-thyroid: O.A.S., opening of air sac; L.G., lymphatic glands: T.C., thyroid cartilage; Tra., trapezius. Other letters "as in fig. 31.
shows that the process has just begun in Dryopithecus. The extent of the attachments of the anterior bellies to the mandible is a point of importance in the study of the skulls of extinct Apes and Man. In the Orang